The present invention relates to a dampening apparatus of a lithographic printing machine or press and more particularly to a nozzle-spray type dampening apparatus thereof including a plurality of nozzles through which dampening liquid is supplied to rollers constituting a dampening train and then supplied to a printing plate through the dampening train.
Such a nozzle-spray type dampening apparatus is for example disclosed in Japanese Utility Model Publication No. SHO 39-28072, Japanese Patent Laid-open Publication No. SHO 63-72549 and Japanese Patent Laid-open Publication No. HEI 3-21452.
The dampening apparatus disclosed in the above known publications are each provided with a cover, as disclosed in detail in the Japanese Utility Model Publication No. SHO 39-28072, for preventing a sprayed dampening liquid from scattering to undesired portions so as the portions may not rust.
In the Japanese Patent Laid-open Publication No. HEI 3-21452, there is disclosed a mechanism for adjusting a distance between a spraying device including nozzles and a peripheral surface of a roller to which the dampening liquid is supplied, as occasion demands, and in the Japanese Patent Laid-open Publication No. SHO 63-72549, there is disclosed a mechanism for easily mounting and dismounting a spraying mechanism to and from a printing machine.
Further, the Japanese Utility Model Publication No. SHO 39-28072 discloses a mechanism for adjusting the spraying amount of the dampening liquid by moving a front end of a spray nozzle, but this mechanism is one for changing an opening degree of the spray nozzle and not one for adjusting a distance between the spraying mechanism and the peripheral surface of the roller to which the dampening liquid is supplied.
In general, the nozzle-spray type dampening apparatus is an apparatus for supplying the dampening liquid to the roller in shape of sector widening in the axial direction of the roller, and in such apparatus, in order to substantially uniformly supply the dampening liquid to the roller surface along the axial direction thereof through a plurality of nozzles arranged side by side, when the spraying device including the nozzles is mounted, it is necessary to properly adjust the distance between the nozzles and the peripheral surface of the roller.
In the nozzle-spray type dampening apparatus disclosed in the Japanese Utility Model Publication No. SHO 39-28072 and the Japanese Patent Laid-open Publication No. SHO 63-72549, stationary structures are employed in which the spraying mechanisms are stationarily located with respect to the rollers to which the dampening liquid is sprayed, and hence, it is difficult to adjust the distance between the spraying mechanism and the roller after the assembling together. Accordingly, when the spraying mechanism and the roller are assembled, it was required to assemble them with high accuracy, resulting in lowering of working efficiency and increasing much mental labor of workers.
On the other hand, the nozzle-spray type dampening apparatus disclosed in the Japanese Patent Laid-open Publication No. HEI 3-21452 is provided with a spraying mechanism capable of adjusting the close and apart movement thereof with respect to the roller to which the dampening liquid is sprayed. Thus, the dampening apparatus of this prior art overcomes the above problem encountered in the nozzle-spray type damping devices disclosed in the Japanese Utility Model Publication No. SHO 39-28072 and the Japanese Patent Laid-open Publication No. SHO 63-72549. However, in this prior art dampening device, since the spraying mechanism is moved integrally with the whole structure of a cover unit, a distance between the front end of the cover unit and the peripheral surface of the roller is widened, which results in that the function for preventing the dampening liquid from scattering is degraded and that the dampening liquid is scraped from the roller peripheral surface through the abutment of the front end of the cover unit against the roller peripheral surface. Furthermore, when the close and apart movement of the spraying mechanism is adjusted, it is vertically displaced in response to this movement, and because of this reason, the dampening liquid spraying angle to the roller peripheral surface is changed, which may result in uneven supply of the dampening liquid to the printing surface, thus being inconvenient.
Still furthermore, in the nozzle-spray type dampening apparatus, there may be caused a case wherein a nozzle is clogged by undesired materials contained in the dampening liquid such as scale or slime, thereby preventing the dampening liquid from smoothly supplying, and in order to obviate such defect, it is necessary to inspect, clean and maintain the spraying device by disassembling the same periodically or as occasion demands, thus being troublesome.
In this view point, in the nozzle-spray type dampening apparatus of the Japanese Utility Model Publication No. SHO 39-28072, since the spraying mechanism is constructed to be integral with the cover unit for preventing the dampening liquid from scattering and is attached, through the cover unit, to a frame of a printing machine, no structural consideration is paid to the mounting or dismounting of the spraying mechanism for its maintenance or inspection. Then, in a case when it is required to dismount the spraying mechanism, it is obliged to entirely remove the spraying mechanism and the cover unit together, and moreover, it is required to accurately adjust the position of these mechanisms with respect to the roller peripheral surface to which the dampening liquid is supplied, requiring much time and labor for the worker, thus being troublesome and undesirable for the worker.
The above problems encountered in the prior art of the Japanese Utility Model Publication No. SHO 39-28072 are solved by the nozzle-spray type dampening apparatus of the Japanese Patent Laid-open Publication No. SHO 63-72549 paying the consideration to the dismounting and mounting of the spraying mechanism for the inspection or the like thereof. However, in the dampening apparatus of the latter publication, the freedom for the dismounting or mounting of the spraying mechanism is extremely limited because connecting means for connecting the spraying mechanism and electrical power supply sources for the spraying mechanism, the dampening liquid supply, and the like are fixed to the frame of the printing machine. Furthermore, in the dampening apparatus of this prior art, the spraying mechanism is enclosed in the cover unit, so that when the spraying mechanism is removed, it is necessary to pay an attention to the removal of the cover unit, thus being inconvenient.
Still furthermore, in the nozzle-spray type dampening apparatus disclosed in the Japanese Patent Laid-open Publication No. HEI 3-21452, it is considered to mount or dismount the spraying mechanism more easily for inspection, for example. That is, a frame of a printing machine is formed with a U-shaped receiving portion opened obliquely upward and an end portion of the spraying mechanism is held by the receiving portion with its rotation being limited. This arrangement solves the problem involved in the apparatus disclosed in the Japanese Patent Laid-open Publication No. SHO 63-72549 as mentioned above. However, in the dampening apparatus of the HEI 3-21452 publication, the spraying mechanism must be mounted or dismounted together with the cover unit, and accordingly, when the spraying mechanism is dismounted or mounted, it must be handled together with the cover unit and the total weight to be handled is heavy, and the center of gravity is at the side of the spraying mechanism, thus being troublesome and inconvenient.